.TH "QwtScaleEngine" 3 "Fri Apr 15 2011" "Version 6.0.0" "Qwt User's Guide" \" -*- nroff -*-
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.SH NAME
QwtScaleEngine \- 
.PP
Base class for scale engines.  

.SH SYNOPSIS
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.PP
.PP
\fC#include <qwt_scale_engine.h>\fP
.PP
Inherited by \fBQwtLinearScaleEngine\fP, and \fBQwtLog10ScaleEngine\fP.
.SS "Public Types"

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.RI "enum \fBAttribute\fP { \fBNoAttribute\fP =  0x00, \fBIncludeReference\fP =  0x01, \fBSymmetric\fP =  0x02, \fBFloating\fP =  0x04, \fBInverted\fP =  0x08 }"
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.RI "typedef QFlags< \fBAttribute\fP > \fBAttributes\fP"
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.SS "Public Member Functions"

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.RI "\fBQwtScaleEngine\fP ()"
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.RI "virtual \fB~QwtScaleEngine\fP ()"
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.RI "void \fBsetAttribute\fP (\fBAttribute\fP, bool on=true)"
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.RI "bool \fBtestAttribute\fP (\fBAttribute\fP) const "
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.RI "void \fBsetAttributes\fP (\fBAttributes\fP)"
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.RI "\fBAttributes\fP \fBattributes\fP () const "
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.RI "void \fBsetReference\fP (double reference)"
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.RI "double \fBreference\fP () const "
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.RI "void \fBsetMargins\fP (double lower, double upper)"
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.RI "double \fBlowerMargin\fP () const "
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.RI "double \fBupperMargin\fP () const "
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.RI "virtual void \fBautoScale\fP (int maxNumSteps, double &x1, double &x2, double &stepSize) const =0"
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.RI "virtual \fBQwtScaleDiv\fP \fBdivideScale\fP (double x1, double x2, int maxMajSteps, int maxMinSteps, double stepSize=0.0) const =0"
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.RI "virtual \fBQwtScaleTransformation\fP * \fBtransformation\fP () const =0"
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.SS "Protected Member Functions"

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.RI "bool \fBcontains\fP (const \fBQwtInterval\fP &, double val) const "
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.RI "QList< double > \fBstrip\fP (const QList< double > &, const \fBQwtInterval\fP &) const "
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.RI "double \fBdivideInterval\fP (double interval, int numSteps) const "
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.RI "\fBQwtInterval\fP \fBbuildInterval\fP (double v) const "
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.SH "Detailed Description"
.PP 
Base class for scale engines. 

A scale engine trys to find 'reasonable' ranges and step sizes for scales.
.PP
The layout of the scale can be varied with \fBsetAttribute()\fP.
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Qwt offers implementations for logarithmic (log10) and linear scales. Contributions for other types of scale engines (date/time, log2 ... ) are welcome. 
.SH "Member Typedef Documentation"
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.SS "typedef QFlags<\fBAttribute\fP> \fBQwtScaleEngine::Attributes\fP"
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Layout attributes. 
.SH "Member Enumeration Documentation"
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.SS "enum \fBQwtScaleEngine::Attribute\fP"Layout attributes 
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\fBSee also:\fP
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\fBsetAttribute()\fP, \fBtestAttribute()\fP, \fBreference()\fP, \fBlowerMargin()\fP, \fBupperMargin()\fP 
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\fBEnumerator: \fP
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.TP
\fB\fINoAttribute \fP\fP
No attributes. 
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\fB\fIIncludeReference \fP\fP
Build a scale which includes the \fBreference()\fP value. 
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\fB\fISymmetric \fP\fP
Build a scale which is symmetric to the \fBreference()\fP value. 
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\fB\fIFloating \fP\fP
The endpoints of the scale are supposed to be equal the outmost included values plus the specified margins (see \fBsetMargins()\fP). If this attribute is *not* set, the endpoints of the scale will be integer multiples of the step size. 
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\fB\fIInverted \fP\fP
Turn the scale upside down. 
.SH "Constructor & Destructor Documentation"
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.SS "QwtScaleEngine::QwtScaleEngine ()\fC [explicit]\fP"
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Constructor. 
.SS "QwtScaleEngine::~QwtScaleEngine ()\fC [virtual]\fP"
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Destructor. 
.SH "Member Function Documentation"
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.SS "\fBQwtScaleEngine::Attributes\fP QwtScaleEngine::attributes () const"Return the scale attributes 
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\fBSee also:\fP
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\fBAttribute\fP, \fBsetAttributes()\fP, \fBtestAttribute()\fP 
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.SS "virtual void QwtScaleEngine::autoScale (intmaxNumSteps, double &x1, double &x2, double &stepSize) const\fC [pure virtual]\fP"Align and divide an interval
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\fBParameters:\fP
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\fImaxNumSteps\fP Max. number of steps 
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\fIx1\fP First limit of the interval (In/Out) 
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\fIx2\fP Second limit of the interval (In/Out) 
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\fIstepSize\fP Step size (Return value) 
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.PP
Implemented in \fBQwtLinearScaleEngine\fP, and \fBQwtLog10ScaleEngine\fP.
.SS "\fBQwtInterval\fP QwtScaleEngine::buildInterval (doublev) const\fC [protected]\fP"
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Build an interval for a value. In case of v == 0.0 the interval is [-0.5, 0.5], otherwide it is [0.5 * v, 1.5 * v] 
.SS "bool QwtScaleEngine::contains (const \fBQwtInterval\fP &interval, doublevalue) const\fC [protected]\fP"Check if an interval 'contains' a value
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\fBParameters:\fP
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\fIinterval\fP Interval 
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\fIvalue\fP Value
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\fBSee also:\fP
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QwtScaleArithmetic::compareEps() 
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.SS "double QwtScaleEngine::divideInterval (doubleintervalSize, intnumSteps) const\fC [protected]\fP"Calculate a step size for an interval size
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\fBParameters:\fP
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\fIintervalSize\fP Interval size 
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\fInumSteps\fP Number of steps
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\fBReturns:\fP
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Step size 
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.SS "virtual \fBQwtScaleDiv\fP QwtScaleEngine::divideScale (doublex1, doublex2, intmaxMajSteps, intmaxMinSteps, doublestepSize = \fC0.0\fP) const\fC [pure virtual]\fP"
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Calculate a scale division. \fBParameters:\fP
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\fIx1\fP First interval limit 
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\fIx2\fP Second interval limit 
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\fImaxMajSteps\fP Maximum for the number of major steps 
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\fImaxMinSteps\fP Maximum number of minor steps 
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\fIstepSize\fP Step size. If stepSize == 0.0, the scaleEngine calculates one. 
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Implemented in \fBQwtLinearScaleEngine\fP, and \fBQwtLog10ScaleEngine\fP.
.SS "double QwtScaleEngine::lowerMargin () const"\fBReturns:\fP
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the margin at the lower end of the scale The default margin is 0.
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\fBSee also:\fP
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\fBsetMargins()\fP 
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.SS "double QwtScaleEngine::reference () const"\fBReturns:\fP
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the reference value 
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\fBSee also:\fP
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\fBsetReference()\fP, \fBsetAttribute()\fP 
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.SS "void QwtScaleEngine::setAttribute (\fBAttribute\fPattribute, boolon = \fCtrue\fP)"Change a scale attribute
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\fBParameters:\fP
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\fIattribute\fP Attribute to change 
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\fIon\fP On/Off
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\fBSee also:\fP
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\fBAttribute\fP, \fBtestAttribute()\fP 
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.SS "void QwtScaleEngine::setAttributes (\fBAttributes\fPattributes)"Change the scale attribute
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\fBParameters:\fP
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\fIattributes\fP Set scale attributes 
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\fBSee also:\fP
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\fBAttribute\fP, \fBattributes()\fP 
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.SS "void QwtScaleEngine::setMargins (doublelower, doubleupper)"
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Specify margins at the scale's endpoints. \fBParameters:\fP
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\fIlower\fP minimum distance between the scale's lower boundary and the smallest enclosed value 
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\fIupper\fP minimum distance between the scale's upper boundary and the greatest enclosed value
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Margins can be used to leave a minimum amount of space between the enclosed intervals and the boundaries of the scale.
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\fBWarning:\fP
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.PD 0
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\fBQwtLog10ScaleEngine\fP measures the margins in decades.
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.RE
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\fBSee also:\fP
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\fBupperMargin()\fP, \fBlowerMargin()\fP 
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.SS "void QwtScaleEngine::setReference (doubler)"
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Specify a reference point. \fBParameters:\fP
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\fIr\fP new reference value
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The reference point is needed if options IncludeReference or Symmetric are active. Its default value is 0.0.
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\fBSee also:\fP
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\fBAttribute\fP 
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.SS "QList< double > QwtScaleEngine::strip (const QList< double > &ticks, const \fBQwtInterval\fP &interval) const\fC [protected]\fP"Remove ticks from a list, that are not inside an interval
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\fBParameters:\fP
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\fIticks\fP Tick list 
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\fIinterval\fP Interval
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\fBReturns:\fP
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Stripped tick list 
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.SS "bool QwtScaleEngine::testAttribute (\fBAttribute\fPattribute) const"Check if a attribute is set.
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\fBParameters:\fP
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\fIattribute\fP Attribute to be tested 
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\fBSee also:\fP
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\fBAttribute\fP, \fBsetAttribute()\fP 
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.SS "virtual \fBQwtScaleTransformation\fP* QwtScaleEngine::transformation () const\fC [pure virtual]\fP"\fBReturns:\fP
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a transformation 
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.PP
Implemented in \fBQwtLinearScaleEngine\fP, and \fBQwtLog10ScaleEngine\fP.
.SS "double QwtScaleEngine::upperMargin () const"\fBReturns:\fP
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the margin at the upper end of the scale The default margin is 0.
.RE
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\fBSee also:\fP
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\fBsetMargins()\fP 
.RE
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.SH "Author"
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